New comparison from European Environmental Agency (EEA) on Trains versus Planes

Train or plane?

Two new studies from EEA draw new light on climate impacts and broader environment impacts from European passenger and freight transport. With the new reports we are again able to refer to very solid European figures, when we are discussing the environmental impacts of a modal shift from planes to rail.

The new reports updates an old EEA study from 2014 which was already in 2019 declared for not-updated.

The first study (briefing) from EEA (A) is giving the greenhouse gas perspective.

The second study (EEA report) (B) is giving a more broad environmental perspective. Here greenhouse gasses are complemented by air pollution and noise. And 20 selected cross border travels are compared.

Both studies have the same weaknesses, which will be mentioned below.

Overall conclusion from EEA

EEA (A) concludes: “Trains are the most efficient form of passenger transport in the EU, with GHG emissions per pkm that are only a fraction of most other modes.”

EEA (B) concludes on page 48: “An analysis of 20 city pairs shows that the environmental costs of rail travel are substantially lower than those of air travel.”

Both studies are comparing apples with bananas. With the aim to compare cross border services, you cannot count a rural diesel railcar within a dataset and compare with aviation. You need to compare between same sort of transport: Cross border aviation shall be compared with high speed trains, EC-trains and night trains. Both studies fails on this issue.

Both studies are also weak when it comes to occupancy rates. All sort of trains goes within the average numbers. And planes only with 100% occupancy (I suppose so from study A, since it is not mentioned at all) or with 80% on the most busy routes (study B).

And on the non CO2 related climate impact from aviation, both studies only use a RFI (or GWP) as low as 1,23 (A) or 1,7 (B).

Study A

Figure 1

Click on the picture to get an enlargement!

Study A is probably giving airplanes 100% occupancy rates, underestimating the climate impact, and comparing with a full range of rail transport (GHG’es and occupancy rates).

Study B

The study is using 20 selected travels in Europe between two major cities with air connections and rail connections of which 7 are < 500 km, 7 are 500-750 km, and 6 are 750 – 1100 km. Distances are calculated as car distance, and rail distance is set to the same. Air distance is set to the shortest line between the two cities (which might be a little bit wrong).

What is the environmental cost in study B?

EEA has selected four elements, that they find comprises the environmental costs:

  • Noise
  • Air pollution
  • Fossil fuel consumption on the move
  • Fossil fuel production
  • Non-CO2 related climate impact related to aviation.

And all elements are calculated in EUR to make it possible to make an overall figure. See this conclusive figure 5.4 (page 55):

Figure 2

Click on the picture to get an enlargement!

To mix so different things as climate, air pollution and noise is a very difficult exercise.

  • How to calculate it correct?

Calculation of noise costs for trains are mentioned at page 86, in EUR per train-kilometer:

  • Highspeed train: 0,97
  • Electric train: 1,06
  • Diesel train: 0,81

As we can see this is a very strange calculation, when the aim is about long distance trains.

But how can we meaningful compare noise from an aircraft and a train?

It is very hard. With all respect to noise and air pollution, we should focus alone on climate impact, as study A.

Anyway it is not too complicated with study B to re-calculate, and lets see where that will take us. Now, let us stick to grams of CO2 per passenger kilometer. The price is in the report 100 EUR per emitted ton of CO2, so figure 5.4 can be re-calculated.

How is the climate impact calculated?

In figure 5.4 (see above) the non CO2-related climate impact from burning jetfuel in the atmosphere (Radiative Forcing Index, RFI) is put on top with dark blue and with a uncertainty scale (thin line). The dark blue bar is representing a RFI of 1,7 on the short range (500 km) on basis of the share of fuel used for flying. The RFI for longer ranges (1000 km) is set to 1,8. (In study A short haul flights are set to 1,0, long distance to 1,7 with an average of 1,23).

That is very strange figures. The overall European recommendation (December 2020) is RFI = 3,0 by Lee et al and endorsed by the EASA. 3,0 is an average. A German study from 2019 goes into details in relation to length of the journey what we need to do. It is J.D. Scheelhaase in Journal of Air Transport Management 75 (2019) pages 68-74 and in this study the RFI of 1,7 is justified for the short distances, but on 1000 km the RFI is rather 3,0 due to the travel in high altitudes.

So let us stick to RFI respectively 1,7 and 3,0 for the two flying distances in study B.

How are occupancy rates calculated?

Again we are facing a strange weakness within the EEA report.

Occupancy rates is in figure 5.4 set to

  • Aviation: 80%
  • Passenger car: 1 passenger (study A 1,6)
  • Highspeed train: 66% (study A it is calculated from average no. in all European train – so a different method)
  • Intercity train: 36%

The two last figures are based in Table A1.7 (page 84). “High speed: based on an EU average occupancy rate of 66 % (estimated based on UIC (2013), Ortega (2013), EEA (2016b), Doomernik (2014), Dinu (2016) and Italo (2016). Intercity: based on average occupancy rate of 36 % (estimated based on CE Delft (2014) and Hayashi et al. (2015).” So the average covers all rail routes in Europe.

How about aviation in study B? It is made from the 20 selected routes. Table A1.2 (page 80). The average here is 76,4, for some reasons it is made to 80%. But the problem is that these routes are selected as the most used routes in Europe, so they cannot at all be representative for all routes in Europe. A more likely estimate is a rate of 60%, but it should be verified!

With cars it is not likely that the average occupancy rate is 1,0 person per car on distances 500-1000 km in Europe. EEA is also mentioning 1,5, as they used in 2014.

Let us stick to these occupance rates: Aviation: 60%, passenger car: 1,5 passengers, highspeed train: 66% and intercity train: 36%.

Night trains in study B

Night trains are mentioned at page 66: “The same applies for the (re-)introduction of night trains, which could offer a strategy to deal with longer rail travel times.”  And on page 68: “Another strategy to deal with longer rail travel times for longer distances (e.g. between 800 and 1 200 km) is an increased use of night trains. The time and money cost of travel is then compensated for by saving the cost of hotel accommodation.”


The two EEA reports does not bring any new facts to the issue of “level playing field”. What could be a very precise figure to bring to daylight is this one:

The average price a transport operator pays per energy unit (for instance kilowatt-hour) to fuel an airplane in Europe and abroad (A1 jet fuel), compared with the price to pay for electricity to an electric train in Europe.

By not providing such a number, it is not possible to have a real picture of the unfair situation. The ETS is not convincing, and will not alone bring level playing field to the transport sector.

The construction of infrastructure

A cradle to grave approach is not used in the studies and neither the impacts from constructions are. It is mentioned, that such figures could be nice to have, but data are not available. But one place constructions are mentioned:

“For new investment in rail to be environmentally beneficial, the environmental impacts from the construction of infrastructure must be compensated for by the reduced environmental impacts made possible by the opening of the new rail link.” (page 19) This is an essential point, when arguing for rail investments, that they are climate-wise sound and justified. But no-where in the EEA report is mentioned new constructions (or extentions) of airports or construction of new motorways. Why not? Can we understand that EEA of course will ague against all extentions of infrastructure related to environmental harming means of transport? It would suit EEA to go open and call for a stop to all investments that will lead to environmental damage.

The real figure of climate impact based on study B

This is the re-estimated figure 5.4 with the climate impact in grams CO2e, as it should be, based upon the arguments mentioned above:

Figure 3
  • Average fossil car: 111 grams CO2e per passenger kilometer
  • Electric car: 26 grams CO2e
  • High speed train: 19 grams CO2e
  • IC electric train: 23 grams CO2e
  • A320 on a 500 km journey: 253 grams CO2e
  • A320 on a 1000 km journey: 343 grams CO2e

So per kilometer journey on European distances the rail journey is around 15 times more climate friendly than aviation.

What difference does it make – as long as trains er more eco-friendly than planes?

Does it make any significant difference if trains are 3, 8 or 15 times more eco-friendly than planes? Yes it does. The margin will provide room for investments and subsidies all the time as long as market prices are not reflecting the real ecological footprint. With a factor 15 more climate friendly railways, it makes a sound economy to engage in large infrastructure investments and big get-trains-on-the-tracks subsidies to follow the green climate decisions.

This article is made by Poul Kattler, Back-on-Track, in Copenhagen, Denmark. It is subject to revision according to dialogue with EEA and contributions here below:

One thought on “New comparison from European Environmental Agency (EEA) on Trains versus Planes”

  1. Interesting information, that has to be studied in more detail to be understood and used (or criticized ! ?).
    Peter Cornelius
    Head of regional subgroup for Berlin-Brandenburg of Passenger Organisation PRO BAHN

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